Cardholder names, card numbers and expiration dates may have been exposed, the company said.

Several other hotel chains reported being hacked last year, including Starwood, Trump Hotel Collection and Mandarin Oriental.

Hyatt said the malware was found at many of its brands, including the Park Hyatt, Hyatt Regency and Andaz. About 100 of the hotels affected were in the U.S. The rest were abroad in cities including London, Paris and Shanghai.